Compression-wave alarm system

ABSTRACT

An alarm system which uses compression waves carried in pipes as the vehicle for telegraphing information. The system includes a compression wave generator and receiver connected to a conduit system to communicate with one another. A device, such as an openable coupling in the conduit system, is so connected to a protected facility that an intrusion thereinto actuates the device to disturb waves then being carried in the conduit system. This disturbance is sensed by the receiver, and used to effect an alarm.

United States Patent Hamilton 1 COMPRESSION-WAVE ALARM SYSTEM [75] Inventor: Clarence L. Hamilton, Longview,

Wash.

[73] Assignee: Crown Zellerbach Corporation, Camas, Wash.

[22] Filed: Sept. 24, 1973 [21] Appl. No.: 400,187

[52] US. Cl. 340/15; 340/274 [51] Int. Cl. 1104b 11/00 [58] Field of Search 340/258, 276, 274, 15;

[56] References Cited UNITED STATES PATENTS [451 May6,1975

Nelkin et al. 340/261 Beeken 181/123 Primary Examinen-Maynard R. Wilbur Assistant Examiner-T. M. Blum Attorney, Agent, or Firm-Kolisch, Hartwell, Dickinson & Stuart [57] ABSTRACT An alarm system which uses compression waves carried in pipes as the vehicle for telegraphing information. The system includes a compression wave generator and receiver connected to a conduit system to communicate with one another. A device, such as an openable coupling in the conduit system, is so connected to a protected facility that an intrusion thereinto actuates the device to disturb waves then being carried in the conduit system. This disturbance is sensed by the receiver, and used to effect an alarm.

6 Claims, 3 Drawing Figures BACKGROUND AND SUMMARY OF THE INVENTION This invention pertains to an alarm system, and more particularly, to such a system which uses compression waves as the vehicle for transmitting alarm information.

In the storing of various dangerous materials, such as explosives and fuels, it is desirable to provide security surveillance over the facilities in which such materials are kept. For various reasons, conventional surveillance methods have not been satisfactory. For example, automatic electrical or electronic surveillance systems present a serious fire hazard, and in many areas are out lawed for use in conjunction with materials of the type indicated. Human surveillance is extremely costly, and is generally not practically providable on a continuous basis.

A general object of the present invention, therefore, is to provide a novel alarm system which is readily usable in conjunction with materials like those named,

carried in a conduit system containing a suitable compression-wave-transmitting medium, such as air, as the vehicle for telegraphing alarm information. In its essential form, the system includes: a generating means which is operable to generate a compression wave having the frequency and power characteristics desired; a receiving means which is capable of detecting the presence of such a wave; a conduit system which operatively interconnects the generating and receiving means and contains a medium suitable for transmitting the compression waves produced by the generating means; and a means connected to the conduit system which can be associated with the protected facility, and which is operable, on an intrusion into that facility, to introduce a disturbance into the compression waves then being carried in the conduit system, which disturbance is noted by the receiving means. A suitable output means is connected to the receiving means for producing an operative output signal on the receiving means noting such a disturbance.

With such construction, a number of important advantages are attained. For example, with compression waves used as described, these can easily and safely be piped into and about a facility containing combustible materials without introducing any fire hazard. The means employed to produce an operative output signal may be located at a suitable remote distance from the protected facility, and may safely be used to generate, if desired, an electrical alarm signal. For example, this output means might be used to turn on a lamp or a bell at some remote location, or it might be used to turn on The means used to create a disturbance in the waves carried in the conduit system may take various forms, all of which may be relatively simple and inexpensive in construction and installation. For example, a preferred disturbing means (illustrated hereinbelow) takes the form of an openable coupling which connects different portions of the conduit system, and which includes relatively movable parts that may be attached to a door or window in a facility. With such a coupling, intrusion into the facility opens the coupling, and reduces the power level of compression waves received by the receiving means. On the receiving means noting a predetermined reduction in the power of received waves, it causes the output means mentioned above to produce its output signal.

These and other objects and advantages which are attained by the invention will become more fully apparent as the description which follows is read in conjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified view of an installation of the alarm system of the present invention;

FIG. 2 is an enlarged fragmentary view taken generally along the line 2-2 in FIG. 1, and showing details of a coupling used in the system of FIG. 1; and FIG. 3 is a view, on about the same scale as FIG. 2, taken along the line 3-3 in FIG. 2, and further illustrating the coupling in the system.

DETAILED DESCRIPTION OF THE INVENTION Turning now to the drawings, and referring first to FIG. 1, indicated generally at 10 is a storage building or facility which is used to house dynamite. The building includes the usual exterior walls 12, in one of which, as can be seen in the figure, is provided a door 14.

Indicated generally at 16 is a compression-wave alarm system which is connected to provide supervisory security control with respect to use of door 14. Included in system 16, and shown within remote dashed block 18 are a sonic-wave transmitter, or generating means, 20, and a sonic-wave receiver, or receiving means, 22. These two components of the system are shown within block 18 to indicate that they are located preferably adjacent one another, and at a location suitably remote from building 10.

Transmitter 20 and receiver 22 are preferably conventional electrically energized devices, located about 50 feet or more from building 10. Details of construction of the transmitter and receiver are not important, and thus these devices are shown only in block form. In system 16, transmitter 20 comprises a variablepower audio oscillator whose output is connected to a suitable sonic transducer, such as a loudspeaker. While various sonic frequencies may be used, a frequency which has been found to be satisfactory is 2,000 Hz., and the oscillator in transmitter 20 operates on this frequency. Receiver 22 takes the form of a conventional dynamic microphone coupled to a suitable amplifier circuitwhose output is connected to'the coil 24a of a solenoid, or output means, 24. Solenoid 24 also includes a normally open switch 24b. Receiver 22 is so adjusted that with its microphone receiving 2,000 Hz. waves above a selected power level, solenoid 24 remains nonenergized. The receiver energizes the solenoid on the received-wave power level dropping below this selected level.

Further included in system 16 is a conduit system, or means, which herein takes the form of a pair of elongated pipes, or conduit sections, 26, 28. While various sizes and styles of pipes may be used, /2 inch I.D. plastic pipe, and appropriate fittings, have been found to work satisfactorily, and are used in the system shown. What might be thought of as the input end, or terminal, of pipe 26 is suitably coupled to the loudspeaker in transmitter 20, with this pipe then extending from the loudspeaker toward and into building 10. For maximum security, it is desirable that this pipe be placed underground, and be hidden where it emerges from the ground both to connect with the transmitter and to enter the building. Such is the case in the installation shown in FIG. 1. Pipe 28 follows a similar path, with what might be thought of as its discharge end, or terminal, suitably coupled to the microphone in receiver 22, and its input end extending into building 10. It should be noted that the exact paths which the pipes follow are not critical, and need not be exactly as depicted in FIG. 1.

According to an important feature of the invention, those ends of pipes 26, 28 which are inside building are interconnected through an openable coupling, shown generally at 30, which coupling is also referred to as a compression-wave disturbing means. In general terms, with door 14 closed, coupling 30 is also closed, and provides a substantially closed connection between the adjacent ends of pipes 26, 28. Further, and also in general terms, coupling 30 is so mounted adjacent door 14 that opening of the door also opens the coupling, and hence the connection between the pipes.

Referring to FIGS. 2 and 3 which show details of coupling 30, here it can be seen that the coupling includes inner and outer coupling parts 30a, 30b, respectively. Inner coupling part 30a receives the ends of pipes 26, 28 through fittings 32, 34, respectively. Part 30a includes bores 36, 38 which communicate through fittings 32, 34, respectively, with pipes 26, 28, respectively. Part 30a is mounted (see particularly FIG. 2) adjacent the top of the door opening provided for door 14.

Coupling part 30b is suitably secured to the upper margin of door 14, in a position wherein, with the door closed (as shown in the figures) it mates with part 30a. Part 30b includes an elongated recess 40 extending partway across its face which confronts coupling part 30a. This recess, with the coupling parts mated, forms a substantially closed connection between bores 36, 38. This can clearly be seen in FIGS. 2 and 3.

Completing a description of what is shown in the figures, and returning again to FIG. 1, connected by means of conductors 42, 44 to the opposite sides of switch 24b is a signaling device 46 which, may, for example, be a radio-frequency transmitter. This transmitter, like the components shown within block 18, must be located a suitable safe distance from building 10. Closure of switch 24b energizes transmitter 46. Transmitter 46 is set up to transmit a signal to some remote monitoring station.

Explaining now how system 16 performs, with transmitter 20 and receiver 22 operating, and door 14 closed, 2,000 Hz. sonic waves are transmitted in pipes 26, 28 and coupling 30. A suitable power level is selected for the operation of transmitter 20 whereby with door 14 closed, receiver 22 just holds solenoid 24 in a nonenergized condition.

Should someone then open door 14 (as shown in dashed lines in FIG. 3), coupling 30 opens up, whereupon the power level of waves received by receiver 22 drops. Receiver 22 then energizes solenoid 24, with resultant energizing of transmitter 46.

It will thus be obvious that system 16 provides an alarm system affording the various advantages described earlier. Its safety for use in conjunction with combustible materials is apparent.

It should be borne in mind that while one form of a system has been disclosed herein, there are various modifications which may readily be made to suit different circumstances. For example, rather than there being continuous wave transmission in the pipes and coupling, pulsed and/or pulsed and coded transmission could be used. Different frequencies could, of course, also be used, including ultrasonic frequencies. Transmitter 20 and receiver 22 may, of course,be located differently than as shown in FIG. 1. A further type of modification which is appreciated is that some disturbance other than power loss could be employed. Frequency variation is one obvious type.

One advantage of the particular system disclosed herein is that the pipes in the conduit system need not necessarily be buried for security reasons. Were the pipes exposed, for example, and were an intruder to tamper with a pipe, as by breaking it, this would produce a power loss to which the receiver would respond with an alarm signal.

Thus, while a preferred embodiment of the invention has been described, and certain modifications suggested, it is appreciated that other variations and modifications may be made without departing from the spirit of the invention.

It is claimed and desired to be secured by Letters Patent:

1. A compression-wave alarm system for detecting an intrusion at-a selected location in a facility through detecting relative movement between parts in the facility which parts move relative to one another with an intrusion at said location, said system in operative condition comprising conduit means defining a space independent of open space within said facility adapted to contain a compression-wave-transmitting medium,

generating means operatively coupled to said conduit means for producing in any such medium contained in said conduit means a compression wave having a predetermined characteristic,

receiving means operatively coupled to said conduit means for receiving a compression wave carried in said conduit means,

compression-wave disturbing means forming a portion of said conduit means, in the effective conduction path therein coupling said generating and receiving means, and operatively coupled to said parts, said disturbing means on the occurrence of an intrusion at said selected location, disturbing and thereby altering the characteristics of a compression wave produced by said generating means and carried in said conduit means through modifying the effective conduction path coupling the generating and receiving means, and

output means operatively connected to said receiving means for producing an output signal on said receiving means receiving a compression wave having characteristics differing from said predetermined characteristics.

2. The system of claim 1, wherein said disturbing means is incorporated in said conduit means between said generating means and said receiving means.

3. The system of claim 2, wherein said disturbing means comprises a device whose physical configuration changes on the occurrence of relative movement between said parts.

4. The system of claim 3, wherein said device comprises an openable-closeable coupling in said conduit means. 7

5. The system of claim 4, wherein said coupling is constructed to open on the occurrence of relative movement between said parts.

6. A compression-wave alarm system for monitoring the use of an entry into a facility where such entry is of the type including an opening and a movable closure means mounted thereadjacent for opening and closing the opening, said system comprising a pair of elongated spaced-apart conduit sections each including an access terminal, and each being adapted to contain a compression-wavetransmitting medium,

generating means operatively coupled to the access terminal in one of said conduit sections for producreceiving means operatively coupled to the access terminal in the other conduit section for receiving any compression wave carried in the section,

changeable-configuration compression-wave disturb ing means operatively coupling said one and other conduit sections and adapted for operative association with said entry, said disturbing means when so associated with said entry, and on use of the entry, operating to disturb and thereby alter the characteristics of a compression wave traveling in said conduit sections between said access terminals, said disturbing means including a pair of relatively movable parts constructed to form an openable coupling between the conduit sections, which coupling opens on use of said entry and under circumstances with the disturbing means operatively associated with the entry, and

output means operatively connected to said receiving means for producing an output signal on said receiving means receiving a compression wave hav ing characteristics differing from said predetermined characteristics. 

1. A compression-wave alarm system for detecting an intrusion at a selected location in a facility through detecting relative movement between parts in the facility which parts move relative to one another with an intrusion at said location, said system in operative condition comprising conduit means defining a space independent of open space within said facility adapted to contain a compression-wavetransmitting medium, generating means operatively coupled to said conduit means for producing in any such medium contained in said conduit means a compression wave having a predetermined characteristic, receiving means operatively coupled to said conduit means for receiving a compression wave carried in said conduit means, compression-wave disturbing means forming a portion of said conduit means, in the effective conduction path therein coupling said generating and receiving means, and operatively coupled to said parts, said disturbing means on the occurrence of an intrusion at said selected location, disturbing and thereby altering the characteristics of a compression wave produced by said generating means and carried in said conduit means through modifying the effective conduction path coupling the generating and receiving means, and output means operatively connected to said receiving means for producing an output signal on said receiving means receiving a compression wave having characteristics differing from said predetermined characteristics.
 2. The system of claim 1, wherein said disturbing means is incorporated in said conduit means between said generating means and said receiving means.
 3. The system of claim 2, wherein said disturbing means comprises a device whose physical configuration changes on the occurrence of relative movement between said parts.
 4. The system of claim 3, wherein said device comprises an openable-closeable coupling in said conduit means.
 5. The system of claim 4, wherein said coupling is constructed to open on the occurrence of relative movement between said parts.
 6. A compression-wave alarm system for monitoring the use of an entry into a facility where such entry is of the type including an opening and a movable closure means mounted thereadjacent for opening and closing the opening, said system comprising a pair of elongated spaced-apart conduit sections each including an access terminal, and each being adapted to contain a compression-wave-transmitting medium, generating means operatively coupled to the access terminal in one of said conduit sections for producing in any such medium contained in the section a compression wave having predetermined characteristics, receiving means operatively coupled to the access terminal in the other conduit section for receiving any compression wave carried in the section, changeable-configuration compression-wave disturbing means operatively coupling said one and other conduit sectionS and adapted for operative association with said entry, said disturbing means when so associated with said entry, and on use of the entry, operating to disturb and thereby alter the characteristics of a compression wave traveling in said conduit sections between said access terminals, said disturbing means including a pair of relatively movable parts constructed to form an openable coupling between the conduit sections, which coupling opens on use of said entry and under circumstances with the disturbing means operatively associated with the entry, and output means operatively connected to said receiving means for producing an output signal on said receiving means receiving a compression wave having characteristics differing from said predetermined characteristics. 